Summary: We are examining the feasibility of expressing various HIV genes in alternative viral vectors to serve as vaccine candidates. Initial work has focused on solving the problems of cloning and expressing HIV genes in Dengue virus and Sindbis virus, both of which have useful biological properties. Candidate HIV genes include env, tat, rev, gag, vif, vpu, vpr, pol, protease and integrase, as well as mutants and fusion derivatives of these genes. Exploration of their efficacy in animal models will be persued in collaboratiion with other laboratories once the basic problems of viral gene delivery are solved.